diff --git a/Eigen/src/Core/products/GeneralBlockPanelKernel.h b/Eigen/src/Core/products/GeneralBlockPanelKernel.h
index 229e96ceb..d2e6f26c8 100644
--- a/Eigen/src/Core/products/GeneralBlockPanelKernel.h
+++ b/Eigen/src/Core/products/GeneralBlockPanelKernel.h
@@ -252,7 +252,7 @@ void evaluateProductBlockingSizesHeuristic(Index& k, Index& m, Index& n, Index n
         // we have both L2 and L3, and problem is small enough to be kept in L2
         // Let's choose m such that lhs's block fit in 1/3 of L2
         actual_lm = l2;
-        max_mc = 576;
+        max_mc = (std::min<Index>)(576,max_mc);
       }
       Index mc = (std::min<Index>)(actual_lm/(3*k*sizeof(LhsScalar)), max_mc);
       if (mc > Traits::mr) mc -= mc % Traits::mr;